It is known to manufacture yarns formed of a number of plies, each of which may be composed of a number of filaments twisted together to provide a yarn of the desired linear density. The twisting action is performed to cause the filaments making up the yarn to form an integrated structure with definite diametral dimensions and with a substantially smooth exterior surface. The operations necessary to form such a twisted structure require the use of multiple processes with their attendant proneness to manufacturing faults with the result that twisted yarn is comparatively time consuming to produce and requires close quality control.
Because of the advantages associated with twistless yarn many attempts have been made to produce such a yarn, the most common method being to cause the elements of the yarn to adhere to one another by the introduction of adhesive in some form. This is sometimes done by putting blobs of material having adhesive properties at elevated temperature along all or selected elements of the yarn then heating the yarn to cause the adhesive to melt and attach itself to the adjoining elements. Another method has been to form one of the elements of a low melting point material and after bringing the appropriate number of elements together to heat the yarn thus formed whereupon the strand of low melting point material melts and acts as an adhesive holding the other strands together. In all these methods while they have produced twistless yarns, the yarns all suffer from the disadvantage that because of the comparatively large quantity of adhesive or low melting point material which must be employed to provide adequate cohesion they tend to be stiff. This is because of the inability of the yarn elements to slide over one another when the yarn is bent. In other words, the yarn tends to act as a solid bar rather than as a laminated structure.
It would be a great advance in the art if there could be produced a flexible twistless yarn with none of its known disadvantages and it is an object of the present invention to provide such a yarn and also to provide a method and apparatus for the production of such a yarn.